Ricochet,
cant really tell and i dont have a lot of knowledge about chufa i cant even say ive ever seen it in person but with all that. i do however have extensive experence with yellow and purple nutsedge . thats exactly what that looks like in the pics you posted if it is nutsegde you need a plan your local extenstion agent will be able to identify nutsedge in about 2 sec.
this was in june how did the food plots do